The aim of quantum illumination (QI) is to detect the presence of a weakly reflective target embedded in a thermal background [1]}. Surprisingly, it was shown that an entangled Gaussian quantum probe, namely the two-mode squeezed vacuum (TMSV) state, enhances the performance of the task and that the enhancement is maximal for low signal energy and large thermal noise [2]}.
Many theoretical developments [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]}, [11]}, [12]}, [13]}, [14]}, [15]}, [16]}, [17]}, [18]}, [19]}, [20]} and experiments [21]}, [22]}, [23]}, [24]}, [25]}, [26]} have followed in the subsequent decade, which are well documented in reviews [27]}, [28]}, [29]}. An extension to radio-wave frequency has been proposed and proof-of-principle experiments have been demonstrated [30]}, [31]}, [32]}, [33]}, [34]}.
